430 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the bacilli blue (methylen-blue). It was found that the nitric acid 

 must not be stronger than 1 : 10 or 1 : 15, as the methylen-blue had the 

 power of expelling the fuchsin. All the same, bacilli with true spores 

 were stained. From, these two series of experiments it was shown that 

 the hollow spaces were never stained, while the true spores in the central 

 series were stained red on a blue ground. On the other hand the weakened 

 cultures which had been exposed to the temperature of 62°-64° and 

 contained spore-like spaces (microspores) were quite dead, and did not 

 germinate on plates. In order to meet the objection that the bacilli 

 might have accidentally lost their capability of forming spores, the 

 author inoculated from the originals on gelatin and agar. In a few days 

 active spore-formation took place at the temperature of the room. 



Bacteria of the Tubercles of Papilionaeese.* — The tubercles in the 

 root of the Leguminosse were first noticed two hundred years ago by 

 Malpighi, who described them as galls. In the last twenty years these 

 formations have been much discussed and various explanations offered 

 as to their origin. Quite lately Prof. M. Ward showed that if Vicia 

 Faha were grown in sterilized media these tubercles did not appear, 

 and that they were probably caused by a fungus. This fungus was 

 supposed by Prof. Ward to be one of the Ustilaginese. 



Herr M. W. Beyerinck has now gone a step farther and lays it down 

 that a bacterium. Bacillus radicicola, is the cause of the tubercles ; so that 

 we are still very much where we were two hundred years ago. 



Now the contents of the tubercles had from their appearance been 

 described in 1885 as "bacteroids" by Brunchorst,| who conceived that 

 they were autonomous formations of the vegetable protoplasm. The idea 

 of the author (Beyerinck) is that these bacteroids, the existence of which 

 is not disputed, originate from or are produced by immigration of the 

 B. radicicola into the roots. To put it into other words, the bacteroids 

 are metamorphosed bacteria which have lost the power of development, 

 and now are virtually albumen corpuscles, though between the two con- 

 ditions there exist many intermediate stages. Hence the tubercles are 

 caused by the infection of the B. radicicola, and this is proved by the 

 fact that they are not produced when the plants are cultivated in sterilized 

 media. The bacillus forms in decoction of bean-stalks and gelatin 

 largish colonies, of irregular size, whitish in colour, and hemispherical 

 in shape. The colonies appear to consist of rods 4 /x, long and 1 fx thick, 

 and of small motile elements 0*9 yu, long and 0*18 ju, thick. These 

 small elements are flagellated, and their motility depends on the 

 presence of oxygen. Smaller colonies also are produced, and in these 

 there seems to be a regular series of transition forms between the typical 

 rodlet and the bacteroids. 



B. radicicola failed to produce either diastase or invertin. The 

 author gives numerous varieties of his bacillus, and divides the varieties 

 into two groups with somewhat different characteristics. 



Natural mode of infection of Vibrio Metschnikovi.|— The disease of 

 fowls, gastroenteritis cholerica, discovered by M. N. Gamaleia to be 

 caused by Vibrio MetscTinikovi, agrees in many clinical and pathological 

 aspects with the cholera of man — temperature, diarrhoea, cramp, acute 



* Bot. Ztg., xlvi. (1888) pp. 725-35, 741-50, 757-71, 781-90, 797-802 (1 pi.)- 

 Cf. this Journal, 1887, p. 788. t Cf. this Journal, 1886, p. 271. 



X Ann. Instit. Pasteur, 1888, p. 552. 



